Emerging technologies for the extraction of bioactives from mushroom waste

Extraction of bioactive compounds for application in nutraceuticals is gaining popularity. For this, there is a search for low-cost substrates that would make the end product and the process more economical. Mushroom waste (stalk, cap, stem etc.) is one such high valued substrate that has received much attention recently due to its rich reserves of terpenoids, polyphenols, sesquiterpenes, alkaloids, lactones, sterols, antioxidative vitamins, anthocyanidins, glycoproteins and polysaccharides, among others. However, there is a need to identify green and hybrid technologies that could make the bioactive extraction process from these substrates safe, efficient and sustainable. To this effect, many emerging technologies (supercritical fluid, ultrasound-, enzyme- and microwave-assisted extraction) have been explored in the last decade which have shown potential for scale-up with high productivity. This review systematically discusses such technologies highlighting the current challenges faced during waste processing and the research directives needed for further advancements in the field.